An MRI on the knee confirmed the full extent of the injury, which he suffered on a non-contact play, per Rapoport. Watson, who tore his left ACL during his freshman year at Clemson, is facing an 8-9 month rehabilitation and should be back in time for the start of the 2018 season.

Texans coach Bill O'Brien did not talk about any issues regarding Watson's knee during his Thursday news conference. The team only listed Watson as limited after the practice session.

"I talked to Deshaun late this afternoon and we are disappointed," Clemson coach Dabo Swinney said. "But he is a person who has had some setbacks in his life and always comes back stronger. Since he went through the rehab [for a torn ACL] before, he knows what it takes.

"All he did after the injury in 2014 was come back and lead us to the National Championship game twice and, of course, we won it last year," Swinney continued. "He started all 30 games the last two years here. I have no doubt he will come back from this. He has the resolve. His work ethic and drive are incredible."

The team officially placed Watson on injured reserve on Friday.

Watson was coming off the most impressive performance of his young career before suffering the injury. He passed for 402 yards and four touchdowns in the Texans' 41-38 loss to the Seattle Seahawks in one of the most thrilling games of the season.

The performance helped him become the first rookie quarterback to ever win AFC Offensive Player of the Month honors on Thursday. He also was named the NFL's Offensive Rookie of the Month.

Watson passed for 1,699 yards over six games and is tied for the NFL lead in passing touchdowns with 19. It was the most passing touchdowns over a QB's first seven career games since 1970, beating Hall of Fame quarterback Kurt Warner's mark. The Texans scored more than 33 points in each of Watson's four October starts.

Since taking over as the Houston's starter in Week 2, Watson led the NFL in points per game (34.7), was sixth in passing yards per game (266.2 average), first in passing TDs (18) and fourth in passer rating (108.4), per NFL Research. Watson, who was selected No. 12 overall by Houston in the 2017 NFL Draft, was on pace to throw 43 touchdowns -- 17 more than any other rookie in NFL history.

Following his incredible performance Sunday against the Seahawks, All-Pro cornerback Richard Sherman praised Watson as a "special player."

"Has there ever been a rookie that does that? It would be hard to find," Sherman told reporters. "Maybe [Michael] Vick from time to time; he was very special in the pocket. But, it wasn't like he was getting out to run. He was getting out to look up and find the open guy. He's going to be a special player in this league. He made plays that very few people in this league, including the top-tier guys, can make."

It's the third high-profile, season-ending injury to hit the Texans in 2017. Three-time NFL Defensive Player of the Year J.J. Watt fractured his tibial plateau and linebacker Whitney Mercilus suffered a torn pectoral muscle in a loss to the Kansas City Chiefs last month. Watt sent Watson his sympathies on Twitter on Thursday night:

Houston's resiliency in the wake of the Watt and Mercilus injuries kept them in the running for the AFC South title. It remains to be seen how much Watson's injury will damage the team's playoff chances.